LINTHICUM HEIGHTS, Md. (WJZ) — Dozens are evacuated from a hotel near BWI after elevated carbon monoxide levels are detected.

Rochelle Ritchie has more on the source of the leak.

Anne Arundel County fire officials say the CO leak was caused by a faulty flue assembly on a water heater, which was located in one of the hotel’s laundry rooms.

Guests and employees at the Westin Hotel in Linthicum Heights were quickly evacuated after Anne Arundel County firefighters moved in and moved everyone out Sunday.

“I called the front desk and they said we have to leave really, really fast,” a guest named Camille said.

Nine people were taken to the hospital. Four were sent to hyperbaric chambers.

The hotel released the following statement:

“Providing a safe environment is the essence of our business and we are working with management to understand the cause of this unfortunate incident. We are very sorry for all those that have been impacted, especially those who were taken to local hospitals. Our main focus at this time is providing assistance to our guests and associates and taking the necessary steps with management to determine the cause and ensure this doesn’t happen again.”

“The call first came out as a medical emergency for an employee,” firefighters said. “The staff there suspected that there might be carbon monoxide poison and requested for additional resources. And once additional resources came in, we ran the meters and found out there was a high level of carbon monoxide poisoning.”

Firefighters searched all rooms at the Westin and evacuated all seven floors. The level of carbon monoxide detected inside the building was deadly.

“We have some counter readings as high as 700 to 800 parts per million. We would consider any reading above nine to be a potential hazard,” firefighters said.

Guests returning to the hotel were surprised to see half a dozen fire trucks outside the building. They were unable to go inside and retrieve pets or any of their belongings.

“As soon as we told them we had pets up in there they ran right up in there and grabbed them for us,” said guest Joe Berggren.

Carbon monoxide is a colorless, odorless and tasteless gas that only reveals itself after attacking the human body.

“Nausea, headache, possible fainting. Of course, unconsciousness is something that we are very concerned of and could be deadly,” firefighters said.

The building has since been ventilated.

“Hopefully with that we’ll be able to go in without any fear,” said Scott Horrigan, guest.

Guests were allowed back inside of the building to retrieve their belongings.